Hydraulic apparatus



F. J. WRIGHT HYDRAULIC APPARATUS March 29, 1949.

2 Sheets-Sheety l Filed NOV. 20, 1942 fir Aam

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HYDRAULIC APPARATUS Filed NOV. 20, 1942 2 Sheets-Sheet 2 ATTORNEY Patented Mar. 29, 1949 2,465,954 HYDRAULIC APPARATUS Fred J. Wright, Powell, Ohio, assignor to The Denison Engineering Company, Columbus, Ohio, a corporation of Ohio Application November 20, 1942, Serial No. 466,304

8 Claims. 1

The present invention relates to an improvement in liquid transmitting devices, such as hydraulic pumps or motors.

More particularly, the invention relates to that type of hydraulic pump or motor in which a member containing cylinders and pistons has a surface thereof in frictional contact with a surface of another member, liquid being supplied to and directed from the cylinders through ports in the surfaces of the members. One of the pump members is moved relative to the other so that the ports leading to the cylinders of the one member are alternately aligned with inlet and outlet ports of the other member. and motors, it has been found that grit or other foreign matter present in the liquid ows through the ports and moves between the sliding surfaces of the members. Grit between these surfaces causes grooves to be worn between the inlet and outlet ports, thereby decreasing the eiciency of the pump or motor.

An object of the present invention is to entrap the grit or foreign matter substantially as soon as it escapes from the port through which it passed.

More particularly, the object of the present invention is to form one or more recesses in one of the surfaces of the pump or motor members so that any grit or particles between the moving surfaces Will be deposited substantially immediately in the recesses.

Other objects and advantages of the invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Fig. 1 is a view, partly in section, of a hydraulic pump embodying the invention;

Fig. 2 is a view taken on line 2-2 of Fig. l, but on a larger scale;

Fig. 3 is a view taken on line 3-3 of Fig. 1, but on a larger scale; and,

Fig. 4 is a view taken on line 4-4 of Fig. 2, but on a larger scale.

Referring to the drawings, although the present invention is equally applicable to a pump or motor, I have shown a hydraulic pump 20 in which a preferred form of the invention is embodied. The pump 2D comprises, essentially, a tubular housing 2|, a stator or port plate 22, a drive shaft 23, a cylinder barrel 24, and a rotatable plate 25.

'Ihe stator 22 is attached to one end of the housing 2| by bolts 28, and the inner face 29 of In such types of pumps (Cl. 10S-162) the stator is provided with complementary arcuate shaped ports and 3|. The port 30, for example, opens into an interior passage in the stator leading to a suitable connection, not shown, for connecting that port with a liquid reservoir, for example, and the port 3| opens into a passage in the stator leading to a connection, not shown, for connecting the port with a high pressure liquid line of a hydraulic system.

The drive shaft 23 is journaled at one end in a suitable bearing 34 supported in the stator 22 and the opposite end of the drive shaft 23 extends outwardly from the housing 2| and is journaled adjacent the latter end in a bearing 35 supported by the housing 2|. Preferably, a suitable packing gland 36 is provided for the shaft 23 for preventing leakage of liquid from the housing 2|. Passages 26 are provided for draining liquid from the recess in the stator into which the end of shaft 23 extends.

The cylinder barrel 24 is bored centrally, as shown at 32, and is attached to the drive shaft 23 by splines 31 on the shaft, the shaft 23 extending through the bore of the barrel.

A plurality of cylinders 39 is formed in the barrel 24, which cylinders extend parallel with the bore of the barrel. Arcuate shaped ports 40 are formed in the cylinder barrel 24 leading from one end of the cylinders 39 to the end face 4| of the barrel. The area of each port 4|) is less than the cross sectional area of the cylinders 39 for causing liquid pressure created in the cylinders by pistons to urge the barrel 24 against the stator 22. The ports 40 are disposed to be in alignment with the arcuate ports 30 and 3| in the stator 22. y'

Each cylinder is provided with a piston 43, which piston is cylindrical in shape and is closed at one end and open at the other. One of such pistons is shown, in section, in Fig. l. The closed ends of the pistons 43 extend from the barrel 24 toward the rotatable plate 25 and the outer ends of the pistons are spheroid and therefore the points of control thereof with the face 53 are removed from the axis of the piston whereby oscillating movements are imparted to the pistons during revolution of the barrel 24.

Coil springs 44, only. one appearing in the drawings, are disposed Within the pistons 43, one end of each of the springs seating against the closed end of each of the pistons and each of the opposite ends seating on anges 45 of thimblelike bearing members 46. The bearing members 46 are rotatably supported by spindles 4l, which spindles extend from base parts 48. The base part 48 of a spindle is formed preferably integrally with the spindle and comprises a circular ring like portion that abuts the end of the cylinder 39. rI 'hese parts 48 are also provided with passages 49 through which liquid can enter and leave the cylinders 39 through the ports 40. The springs 44 continually urge the pistons 43 outwardly against the plate 25 and urge the barrel 24 against the stator 22.

The plate 25 is annularly shaped and surrounds the drive shaft 23, but it is not connected with the shaft. The plate 25 is supported at the periphery thereof by a suitable friction reducing bearing 52. The bearing 52 is carried by the housing 2| so that the face 53 of the plate 25 abuts the ends of the pistons 43 and is tilted at an angle to the axis of the barrel 24.

The shaft 23 can be considered as a driving shaft when the apparatus functions as a motor or can be driven by any suitable motor for rotating the cylinder barrel 24. When the barrel 24 is rotated, the pistons 43 are reciprocated in the cylinders 39 by the wedging effect caused by the plate 25, and the springs 44. Assuming that the shaft rotates counterclockwise, as viewed in Fig. 3, the ports 40 of the cylinders 39 moving downwardly are in alignment with the arcuate port 30 of the stator 22 and the pistons 43 are moving outwardly of these cylinders, causing liquid to be drawn into the cylinders through ports 30 and 40. The ports 40 of the cylinders 39 moving upwardly are in alignment with port 3l and the pistons in these cylinders move inwardly, forcing the liquid from the cylinders 39 out through ports 40 and 3i.

In the usual hydraulic systems, oil is used as the liquid or power transmitting medium, and this oil quite often contains minute particles of grit and the like, which grit, at times, escapes from the inlet ports of the stator and is ground between the contacting faces of the stator 22 and barrel 24. This grit scrapes and scores the surfaces of the faces, causing leakage between the ports and across the faces of the barrel and stator. Obviously, this decreases the efficiency and life of the pump. I have discovered that by forming one or more closed recesses in the face of the stator intermediate the ends of the ports therein, grit and other foreign substances escaping from the ports are entrapped in these recesses and are thereby removed from between the abutting faces. I prefer -to form these recesses by drilling a plurality of holes 55 in the face 29, which holes, in the embodiment shown, are considerably less in diameter than the width of the arcuate ports 30 and 3l. I prefer to drill a series of these holes in staggered relation so that any grit issuing from the port 30, for example, will be swept into-at -least one or more of the openings, regardless of which portion of the port the grit escapes onto the face 29. Preferably, one or more of the openings 55 are so disposed that they are atleast partially outside the area swept by the ports 40 so that grit escaping latterly from the ports will be entrapped. I have found that these holes may be relatively shallow and may form closed recesses.

By my invention. the life of a stator face can be materially prolonged and the emciency of the pump or motor, in which the invention is embodied, maintained. This is accomplished by eliminating scoring of the surfaces between the moving members of the pump or motor due to the presence of grit in the liquid transmitted by the pump or motor.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. In a fluid pressure energy translating device having a plurality of cylinders and pistons reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with at, annular, sealing surfaces in running engagement, the first of said members having fluid conducting passages terminating at the sealing surface in spaced ports, the second member having spaced ports in its sealing surface communicating with;v said cylinders, the ports in the latter member communicating successively with the ports in the other member during relative rotation of said members, said iirst member having dirt-trapping sections disposed in the sealing surface between adjacent ports for intermittent alignment with the ports of the other member when relative movement between said members occurs, each of said dirt-trapping sections having a plurality of recesses of smaller diameter than the width of the port intermittently aligned therewith, said recesses being disposed to make the dirt-trapping sections at least as wide as the width of any of said ports whereby any foreign matter escaping from any of the ports to the plane of surface contact of the two said members is entrapped in a recess.

2. In a fluid pressure energy translating device having a plurality of cylinders and pistons reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with flat, annular, sealing surfaces in run-l ning engagement, the rst of said members having fluid conducting passages terminating at the sealing surface in spaced ports, the second member having spaced ports in its sealing surface communicating with said cylinders, the ports in the latter member communicating successively with the ports in the other members during relative rotation of said members, said rst member having dirt-trappingareas disposed in the sealing surface between adjacent ports for intermittent alignment with the ports of the other member when relative movement between said members occurs, each of said dirt-trapping areas having a plurality of openings of smaller diameter than the width of the port intermittently aligned therewith, said small diameter openings being arranged in staggered relation, the dirttrapping areas being at least as wide as the width of any of said ports whereby any grit or like foreign matter escaping from any port and moving between said surfaces is entrapped in one of said openings.

3. In a fluid pressure energy translating device having a cylinder and piston reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with flat annular sealing surfaces in running engagement. the rst of said members having fluid conduct# ing passages terminating at the sealing surface in spaced ports, the second member having a port in the sealing surface communicating with said cylinder. the port in the second member alternately communicating with the ports in the other member during relative rotation of said members, the portions of the sealing surface of said rst member between the ports therein having a plurality of circular depressions formed therein for registration with the port in the second member during relative movement of said members, the diameter of each depression being less than the widths of said ports, adjacent depressions being located at unequal distances from the axis of relative rotation of said members.

4. In a fluid pressure energy translating device having a cylinder and piston reciprocable 'therein, a rotary valve structurecomprising two relatively rotatable members provided with flat annular sealing surfaces in running engagement, the rst of said members having fluid conducting passages terminating at the sealing surface in spaced ports the second member having a port in the sealing surface communicating with said cylinder, the port in the second member alternately communicating with the ports in the other member during relative rotation of said members, the portions of the sealing surface of said first member between the ports therein having a plurality of circular depressions formed therein, the diameter of each depression being less than the widths of said ports, adjacent depressions being located at unequal distances from the axis of relative rotation of said members, said depressions being so spaced from said axis that the outer edge of any selected depression will be spaced at a greater distance from the axis than the inner edge of the depression disposed the next greater distance from said axis.

5. In a fluid pressure energy translating device having a cylinder and piston reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with flat annular sealing surfaces in running engagement, the first of said members having fluid conducting passages terminating at the sealing surface in spaced ports the second member having a port in the sealing surface communicating with said cylinder, the port in the second member alternately communicating with the ports in the other member during relative rotation of said members, the portions of the sealing surface of said rst member between the ports therein having circular depressions formed therein, the centers of said depressions lbeing disposed substantially equidistant from the axis of relative rotation of said members as the inner and outer edges of the ports in said rst members, and an additional depression in said surface, the center of said additional depression being the same distance from said axis as the centers of said ports.

6. In a uid pressure energy translating device having a cylinder and piston reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with at annular sealing surfaces in running engagement, the first of said members having fluid conducting passages terminating at the sealing surface in spaced ports the second member having a port in the sealing surface communicating with said cylinder, the port in the second member alternately communicating with the ports in the other member during relative rotation of said members, the portions of the sealing surface of said rst member between the ports therein having circular depressions formed therein, the centers of certain depressions being disposed approximately the same distance from the axis of relative rotation of said members as the inner and outer edges of the ports in said rst member, and additional depressions in said surface, the

Number centers of said additional depressions being disposed at distances from said axis greater than the inner edges of said ports and less than the outer edges thereof, said depressions being of such width that the full width of the port in the second member is bridged thereby during movement of said port between the ports in said first member.

'7. In a fluid pressure energy translating device having a cylinder and piston reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with flat annular sealing surfaces in running engagement, the first of said members having fluid conducting passages terminating at the sealing surface in spaced ports the second member having a port in the sealing surface communicating with said cylinder, the port in the second member alternately communicating with the ports in the other member during relative rotation of said members,

the portions of the sealing surface of said first member between the ports therein having depressed areas each of less width than the port in said second member, the depressed areas being so arranged that the combined width is sufficient to extend across the full width of the port in the second member during movement thereof between the ports in said rst member.

8. In a fluid pressure energy translating device having a cylinder and piston reciprocable therein, a rotary valve structure comprising two relatively rotatable members provided with at annular sealing surfaces in running engagement, the rst of said members having duid conducting pasages terminating at the sealing surfaces in spaced ports the second member having a port in the sealing surface communicating with said cylinder, the port in the second member alternately communicating with the ports in the other member during relative rotation of said members, the portions of the sealing surface of said first member between the ports therein having a plurality of openings registering with the port in said second member during the relative movement of said members, said openings being spaced at various distances from the axis of relative rotation of said members, the width of each opening being less than the width of the ports.

FRED J. WRIGHT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date Williams et al May 20, 1913 Egersdorfer Sept. 2, 1924 Craig July 5, 1932 Durner July 12, 1932 ,Ferris Feb. 2, 1937 Thoma Apr. 25, 1939 Zimmerman July 7, 1942 Wegerdt Sept. 29, 1942 Vickers Oct. 13, 1942 FOREIGN PATENTS Country Date France July 7, 1930 Number 

